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On kwi 21 2016, at 1:20 am, Yves Piguet <yves.piguet@gmail.com> wrote:
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<p>On 21 avr. 2016, at 00:26, Michalis Kamburelis wrote:</p>
<p>> 1. IMHO, it would be more consistent to specify scale treatment such<br>> that factor=0 means identity and factor=1 means "use the original<br>> Transform".</p>
<p>It's actually the case.</p></blockquote><div class="gmail_quote"><br></div><div class="gmail_quote">You're absolutely right. Sorry, I didn't look closely enough at your equation. Looking closer, indeed </div><div class="gmail_quote"><br></div><div class="gmail_quote">- factor=0 means you get sign(s) * exp(0) which is 1 or -1, depending on original scale sign.</div><div class="gmail_quote">- factor=1 means you get back the original value.</div><div class="gmail_quote"><br></div><div class="gmail_quote">This is cool. Still "factor=0" does not make "identity" in case of negative original scale (it makes -1). But this seems OK, even an advantage (interpolating between negative scale and identity seems not much useful, better to reach -1 in case of a negative scale).</div><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<p>> E.g. set "scale = lerp(factor, 1, scale)". This makes<br>> "scale" interaction with "factor" similar to how "factor" affects<br>> "translation" and "rotation" in your proposal.</p>
<p>But then, extrapolating is less practical: you get a degenerated zero scale when factor is -1, and e.g. 2s-1 when factor is 2, which isn't very useful.</p>
<p>I've written the handling of scale as a special case, but actually plain multiplication of the translation and the rotation can also be seen as a kind of logarithmic modulation of the transform. In all cases, if factor is 2, it has the same effect as applying the transform twice; if factor is 0.5, applying it twice has the same effect as the original transform.<br></p></blockquote><div class="gmail_quote"><br></div><div class="gmail_quote">Good point, and it makes me agree with your equations 100%:) I see that the treatment of translation/rotation/scale is actually consistent. Great!</div><div class="gmail_quote"><br></div><div class="gmail_quote">Best regards,</div><div class="gmail_quote">Michalis</div><div class="gmail_quote"><br></div>
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